Lab 3 the axilla
Terms
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- what forms the pectoral girdle?
- the pectoral girdle is formed by the scapulae & clavicles, and is joined to the manubrium of the sternum by the clavicle
- what does the pectoral girdle do?
- the pectoral girdle connects the axial skeleton to the free parts of the upper limb
- what are the two necks on the head of the humerus?
- the anatomical neck (which is more superior/proximal) and the surgical neck (which is just below the large part of the humerus and encircles it more inferiorly/distally)
- what muscle inserts on the intertubercular sulcus?
- the latissimus dorsi muscle inserts on the intertubercular sulcus
- where does the teres major insert?
- anterior medial lip of the intertubercular sulcus
- what muscle inserts on the lateral lip of the bicipital groove?
- the pectoralis major muscle
- where is the deltoid tuberosity?
- lateral edge of the humerus about halfway down the bone
- what lies in the spiral groove of the humerus?
- the radial artery and the profunda brachii artery and vein
- where do the teres major and minor muscles originate?
- t. major originates on the inferior angle of the scapula; t. minor originates on the lateral edge of the scapula just superior to the origination site of t. major
- describe the boundaries of the axilla
-
anterior: pec. major & minor and associated pectoral & clavipectoral fascia
posterior: scapula, subscapularis, t. major, & lat. dorsi
medial: serratus anterior, first 4 ribs & their intercostals
lateral: intertubercular groove of humerus - what is the apex of the axilla?
- apex = entrance from neck to axilla (cervico-axillary canal b/w 1st rib, clavile & subscapularis muscle)
- what does the axillary sheath do?
- it covers the proximal segments of the brachial plexus & axillary vessels
- what is the blood vessel that feeds the axilla?
- the axillary artery
- where does the axillary artery begin & end?
- begins at lateral edge of first rib (as a continuation of subclavian arter) and ends at lower border of teres major (becomes the brachial artery)
- the pectoralis minor divides the axillary artery into 3 parts. name their major sub-branches
-
1st part: 1. supreme thoracic artery
2nd part: 1. thoracoacromial artery
2. lateral thoracic artery
3rd part: 1. posterior circumflex humeral a.
2. anterior circumflex humeral a.
3. subscapular a. - how does one distinguish b/w anterior & posterior circumflex humeral arteries?
- posterior is larger
- what blood vessel drains the axilla and what are its boundaries?
-
the axillary vein:
-lies medial to axillary a. and lateral to 1st rib
-formed by joining of brachial & basilic veins at inferior edge of teres major - which nerve does the lateral thoracic artery run alongside?
- long thoracic nerve
- name the 5 groups of axiallary lymph nodes
- apical, pectoral, subscapular, humeral, & central
- where do apical nodes receive lymph from? pass it on to?
-
receive from all other axillary nodes!
feed into > subclavian lymphatic trunk > right lymphatic duct on R & thoracic duct on L side of body - where are the pectoral nodes?
- medial wall of axilla
- where are apical nodes?
- apex of axilla
- where do pectoral nodes receive from? feed into?
-
-receive from anterior thoracic wall (including breast)
-feed into central & apical nodes -
subscapular nodes lie on posterior axillary fold & subscap. vessels.
receive from?
feed into? - posterior thoracic wall/scapular region --> subscap nodes! --> apical & central nodes
- drainage pattern of humeral (lateral) nodes (they lie posterior to axillary vein)?
- upper extremity lymph (EXCEPT that carried along cephalic vein) -->
- central nodes are where?
- deep to pec minor along part 2 of axillary a.
- central group drainage?
- pectoral, subscapular, & humeral nodes --> CENTRAL NODES --> apical nodes
- what is the brachial plexus?
- the major nerve network supplying the upper limb (begins in neck, ends in axilla)
- what does axillary nerve innervate?
-
1. deltoid
2. teres minor - what innervates the subscapularis?
- upper subscapular nerve
- what does thoracodorsal innervate?
- latissimus dorsi
- what roots are the brachial plexus derived from?
- C5-T1 ventral rami
- what is the order of breakdown of the BP?
- roots > trunks > divisions > cords > branches
- what makes up the M?
- L to R: musculocutaneous, lateral root branch of the median nerve, medial root branch of the median nerve, ulnar
- what runs beneath the M? what are its branches?
-
posterior cord;
it splits into radial and axillary nerves;
also it has three branches off it first: the lower, middle, and upper subscapular - what may or may or not be a branch off the post. cord at the site of the middle subscap. nerve branhc?
- thoracodorsal nerve :-)
- what are the branches of the lateral cord?
-
first: lateral pectoral nerve (named for branch site, NOT pectoral location)
second: musculocutaneous nerve and lateral root branch of the median nerve - what branches of the medial cord?
-
first:
-medial pectoral nerve (again , named for BRANCH SITE not pec site)
second:
-medial cutaneous nerve of the arm
-medial cutaneous nerve of the forearm
third:
-medial root branch of the median nerve
-ulnar nerve - what is the posterior cord often covered by?
- the axillary artery
- a lesion of what nerve causes 'winged scapula'? by what mechanism?
-
long thoracic nerve; arises from ventral rami of C5,6,and7
("five and six and seven,
flap your scaps and go to heaven")
serves serratus anterior which holds scap down; lesion allows it to fly up - what serves the rhomboid minor & major and levator scapulae?
- dorsal scapular nerve (ventral rami of C5)
- what does suprascap. nerve innevrvate?
- (c5,6) supra- and infra-spinatus
- what lies in the spiral groove?
- the radial artery and the profunda brachii artery and vein